In reply to Prof. Perelman, there could be a series of different measures we
could construct to indicate ASNLT, all with an applied validity.
In empiricist theory, a concept is only as good as our ability to measure
the observables to which it refers.
But in realist theory, a concept can refer to something real, but we might
measure that in many different ways, and our measurements might not be
perfect - in other words, the real thing to which the concept refers does
not depend for its reality on measurement, and the validity of the concept
does not depend on its measurability.
It is only that in attempting to devise measures for a concept, we are
forced to get very exact about what we mean by the concept, and what the
concept entails.
Jurriaan